1. Field of the Invention
This invention generally relates to a bicycle derailleur. More specifically, the present invention relates to a rear bicycle derailleur, which is preferably mountable on the end of a rear hub axle, and which preferably includes a cable support structure that is non-movable relative to the bicycle frame.
2. Background Information
Bicycling is becoming an increasingly more popular form of recreation as well as a means of transportation. Moreover, bicycling has become a very popular competitive sport for both amateurs and professionals. Whether the bicycle is used for recreation, transportation or competition, the bicycle industry is constantly improving the various components of the bicycle. One component that has been extensively redesigned is the bicycle derailleur.
Typically, a bicycle derailleur has a base member and a chain guide movably coupled to the base member via a linkage assembly. The base member is coupled to the frame of the bicycle. The chain guide is configured to move the chain laterally over a plurality of rear sprockets. A spring typically biases the chain guide to an innermost or outermost position relative to the sprockets. A Bowden-type control cable with an outer sheath and an inner wire is typically coupled to the derailleur and to a conventional shift control device.
The chain guide of a derailleur includes a pair of shift or guide plates arranged to move the chain laterally back and forth. The rear chain guide includes a pair of pulleys mounted between the shift plates, while the front chain guide is absent pulleys. With the rear chain guide, the chain is wrapped around both pulleys in an S-shaped manner between the guide plates in order to efficiently guide the chain to the appropriate sprocket during shifting and in order to appropriately tension the chain. The front derailleur is usually coupled to the seat tube of the frame, while the rear derailleur is usually coupled to the rear triangle of the bicycle frame adjacent the rear wheel.
The rear derailleur is usually mounted at a spaced location from the hub axle. Thus, the frame often has a portion extending away from the hub axle to which the rear derailleur is mounted. The rear derailleur also usually has a mounting structure for mounting it to the frame extension. While this arrangement works well, this type of arrangement is relatively complicated using numerous parts. Thus, this type of arrangement can be relatively heavy. Moreover, this type of arrangement can be relatively complicated and/or expensive to manufacture and/or assemble due to the numerous parts. Additionally, typical rear derailleurs have a base member that pivots about a fixed member that is fixed to the frame extension. The movable base member usually has an outer cable holder that receives the outer sheath of the shift cable. The cable holder moves when base member moves. While such an arrangement works well, such an arrangement can lead to decreased shifting performance that is not as effective as desired by some riders.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved bicycle derailleur. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.